The desirability of providing fabric softening and static control benefits to fabrics which are laundered and are then dried in an automatic clothes dryer is well known. However, since the compositions which provide fabric softening and static control benefits are generally separate from the detergent composition used to clean the fabrics, their use, in order to obtain these benefits, results in some degree of inconvenience to the person doing the laundry. For example, the detergent composition must be measured out and added at the start of the washing cycle, while the fabric softening and static control composition requires a separate measuring operation and is usually added to the washing machine at a different time during the washing cycle. Thus, the use of most softening/static control compositions requires the inconvenience of additional pouring and measuring operations, as well as the necessity of having to remain close to the washing machine during its operation, so that the composition may be added at the proper time.
Various solutions to this problem have been proposed in the art. Detergent compositions, as well as fabric conditioning compositions, have been separately incorporated with water-insoluble substrates for addition to the washing machine or the automatic dryer during the laundering process. These compositions have the advantage of eliminating the additional pouring and measuring steps generally attendant to the use of conventional powder and liquid softening and static control compositions, thereby reducing the chance of spillage and waste. U.S. Pat. No. 3,694,364, Edwards, issued Sept. 26, 1972, teaches the use of an amine-coated modified cellulosic substrate which releasably contains a detergent composition. The substrate is added to the wash solution in order to introduce the detergent composition into the washing system, while the substrate scavenges and adsorbs undesirable dirt and anionic dyes which are present in the laundry solution. However, the use of such a composition still requires the separate measuring and addition of the fabric conditioning/static control composition at a later time in the laundering cycle, if such a benefit is desired.
Many patents, such as U.S. Pat. No. 3,442,692, Gaiser, issued May 6, 1969; U.S. Pat. No. 3,632,396, Zamora, issued Jan. 4, 1972; U.S. Pat. No. 3,686,025, Morton, issued Aug. 22, 1972; and U.S. Pat. No. 3,936,538, Marshall et al, issued Feb. 3, 1976, teach methods of incorporating various fabric conditioning compositions, such as static control compositions, on insoluble substrates. When these substrates are added to an automatic dryer, or to the rinse cycle of an automatic washer, the fabrics being laundered receive the fabric conditioning benefit. However, even with these compositions, the detergent composition required to clean the fabrics, must be separately measured out and added to the laundry solution, and the fabric conditioning substrate compositions must be added at another time during the laundering process.
One possible solution to this inconvenience would be to include the fabric conditioning agent in the detergent composition itself. However, additional problems result when various quaternary ammonium compounds, which are known in the art to possess beneficial antistatic properties, are placed in detergent compositions which contain anionic surfactants, which are commonly employed in the laundering of fabrics. The opposite electrical charges of the two compounds lead not only to the mutual attraction of the surfactants, which results in the formation of insoluble compounds and the depletion of the respective materials, but also to reversal of the electrical charges upon fabric surfaces exposed to the wash liquid. This reversal results in undesirable effects such as increased soil redeposition on fabrics and poor soil removal. U.S. Pat. No. 3,936,537, Baskerville, Jr. et al, issued Feb. 3, 1976, discloses particulate detergent compositions, having static control particles within a specific size range, which permit the incorporation of quaternary ammonium fabric conditioning compounds into granular or powder-form detergent compositions, and which yield both cleaning and static reduction benefits to fabrics washed therewith. The attainment of effective static control benefits using such compositions depends upon the entrapment of the quaternary ammonium compound-containing particles in the fabrics during the washing process, which, under certain conditions, may result in the undesirable buildup of such particles in laundered fabrics or in various parts of the automatic washer and dryer. In addition, a certain amount of these quaternary ammonium-containing particles will fail to become so entrapped and, thus, their static control effect will be lost.
It is thus an object of the present invention to provide a substrate article which efficiently yields fabric conditioning benefits when used in the laundering process.
It is a further object of the present invention to formulate a laundry article which provides both cleaning and fabric conditioning benefits to fabrics laundered with it.
It is also an object of this invention to provide a convenient, easy to use detergent composition, which does not require limitations as to particle size necessary in order to obtain static control, and which yields fabric-care benefits in both the automatic washer and the automatic dryer.
It is a still further object of the present invention to provide a method for obtaining both cleaning and static control benefits for laundered fabrics, utilizing a substrate detergent composition.